If you live in northwest Houston, you have probably seen it. White crust on the shower head. Spots on glasses that come out of the dishwasher. A film on the shower door that comes back a week after you clean it. That is hard water, and the City of Houston's own water report shows why it shows up.
I want to walk you through what that report says, in plain terms, and what it does and does not tell you about the water at your house.
What the City of Houston report says about hardness
Every year, the City of Houston publishes a water quality report. The Houston Water Quality Report 2025 covers the City's main system. For total hardness, it lists an average of 135.5 mg/L. The lowest sample was 43.5 mg/L and the highest was 229 mg/L.
Water treatment people usually talk in grains per gallon. To convert, you divide mg/L by about 17.1. That makes the City's average about 7.9 grains per gallon, with a range of about 2.5 to 13.4 grains.
One more thing the report shows: it lists hardness under its secondary standards with no limit (it says "NA"). Hardness is not something the City treats as a safety problem. It is a comfort and upkeep problem.
Is that hard? Here is the scale
The U.S. Geological Survey sorts water into four groups, measured in mg/L:
- 0 to 60: soft
- 61 to 120: moderately hard
- 121 to 180: hard
- More than 180: very hard
So the City's average of 135.5 mg/L lands in the "hard" group. Its lowest sample, 43.5, was soft. Its highest, 229, was very hard. That is a big spread, and it is the main reason I do not trust a citywide average to tell you about one kitchen faucet.
Part of the reason is where the water comes from. The report says 90.3% of the City's water was surface water from Lake Conroe and Lake Houston (San Jacinto River) and Lake Livingston (Trinity River). The other 9.7% came from 104 wells in the Evangeline and Chicot aquifers, deeper than 750 feet. The mix that reaches a house depends on where that house is.
What hard water does inside your home
The USGS says hardness is not a health concern, but it can be a nuisance. Here is what that nuisance looks like, in the USGS's own terms:
- Soap reacts with the calcium in hard water and forms soap scum, so it takes more soap and detergent to get your hands, hair and laundry clean.
- When hard water is heated, as it is in your water heater, solid scale can form. The USGS says that scale can shorten the life of equipment, raise the cost of heating water, and lower the efficiency of electric water heaters.
- Over time, scale can build up inside pipes and slowly cut water flow.
That is why I think about hardness as a whole-house problem, not just a spotty-glass problem. Your water heater, your dishwasher and your washing machine all see the same water your shower head does.
If you are on a MUD, these numbers may not be yours
Here is the part a lot of people miss. Much of northwest Harris County does not get its water from the City of Houston at all. It comes from a municipal utility district, or MUD. The North Harris County Regional Water Authority says 143 MUDs take part in its groundwater reduction plan, and it delivers surface water to 61 districts. So two neighborhoods a few miles apart can be on lake water, well water, or a mix.
I have not read the reports for the MUDs in our area, so I am not going to guess at their numbers. You do not have to guess either. Every public water supplier has to publish a yearly water quality report. It is often called a Consumer Confidence Report, or CCR.
- Look at your water bill. It names who supplies your water.
- Find that supplier's most recent Consumer Confidence Report. Your MUD's operator or website should have it, or you can call the number on your bill and ask for it.
- Look for the line called "Total Hardness." If it is in mg/L, divide by 17.1 to get grains per gallon.
Even then, a report is an average for a whole system. A test of your own tap is the surest answer.
What to do about it
If scale, spots and soap film are your main problem, a water softener is the piece that fixes it. It takes out the calcium and magnesium before the water reaches your pipes and appliances.
If you also notice a chlorine-like taste or smell, that is a different job. A softener does not handle that. Whole-home filtration does, and the two often go in together. I wrote about that taste and smell in my post on chloramine.
Not sure which you need? That is normal. I wrote a side-by-side guide to softeners, filters and reverse osmosis for exactly that question.
When you are ready, ask me for a free quote. I will ask where your water comes from and what is bugging you about it, and I will give you one honest, upfront price for the system that fits your house. Call me at (346) 649-1463, or send the form.
Questions about your water? Call Mathew.
Free quote, honest upfront pricing, and a system that fits your house.
Sources
- City of Houston, Houston Public Works, Houston Water Quality Report 2025, Main System (TX1010013). Read 20 Oct 2026, re-checked 22 Oct 2026.
- U.S. Geological Survey, Water Science School, "Hardness of Water". Read 22 Oct 2026.
- North Harris County Regional Water Authority. Read 20 Oct 2026.